Pneumatically operated electric switch



Feb. 24, 195-9 7 R. L. ARMSTRONG ETAL 2,875,291

PNEUMATICALLY OPERATED ELECTRIC SWITCH Filed Nov. 1, 1956 2 Sheets-Sheet 1 F g-l ing 40 KT Raymond L Armstrong Gerald H. Morenus George H. More/ms INVENTORS.

Feb. 24, 1959 R. 1.. ARMSTRONG ET AL 7 PNEUMATICALLY OPERATED ELECTRIC SWITCH Filed Nov. 1, 1956 Fig.6

2 Sheets-Sheet 2 Raymond L. Arms/rang Gerald H. Morenus George H. More/70s IN V EN TORS.

United States Patent "ice PNEUMATICALLY OPERATED ELECTRIC SWITCH Raymond L. Armstrong, Cortland, and Gerald H. Morenus and George H. Morenus, Homer, N. Y.

Application November 1, 1956, Serial No. 619,751 7 Claims. (Cl. 200-81) This invention generally relates to a novel electric switch construction and more particularly an electric switch which is operated from a remote point by employing a fluid pressure actuated contact bridging member.

An object of the present invention is to provide a novel construction of a device to replace the conventional push button switch employed in conjunction with hospital call systems or similar arrangements. In present call systems a push button electric switch is connected to a master call board by an electrical conductor wherein actuation of the switch will cause a signal to be energized, thus advising those in attendance that the patient is desirous of attention. The arrangement of an electric cord with a push button switch at the patients end is highly objectionable from the standpoint of maintenance, since the cord quite often becomes frayed or otherwise damaged and thus endangers the patient, and where a patient is in an oxygen tent, the push button switch and call cord must be taken from the patient to eliminate any possibility of an explosion or fire from any spark generated by the switch within the tent. Thus, patients in an oxygen tent have no means of calling a nurse. Accordingly, it is the primary object of the present invention to overcome the objections to the push button switch by providing a pneumatically actuated switch, with the contacts which selectively open or close the circuit being located remotely from a squeeze bulb provided for actuation by the patient, whereby the patient may call a nurse by squeezing a squeeze bulb for actuating a remote switch, thus eliminating any possibility of a spark causing an explosion under an oxygen tent and also eliminating any possibility of shock from a worn or damaged electric cord.

A further object of the present invention is to provide 'a squeeze bulb actuated electric switch for energizing a "switch of the present invention to be employed with that type of signal system employing a circuit in which the signal is operated by breaking the circuit, as well as in those "circuits in which the signal is actuated by completing the circuit.

Another object of the present invention is to provide a pneumatically actuated electric switch in accordance with the preceding objects in which a solenoid coil is provided in the electric circuit for retaining the signal device in 'energized relation until such time as the nurse manually resets the system.

' Yet another important 'object of the present invention '--is to provide a pneumatically operated electric switch for u'se'in hospital call systems which is extremely simple in "construction, adaptable to various types of hospital call systems, safe in operation, adaptable for'its particular pur-.'

poses and relatively inexpensive in manufacturing cost.

2,87 5,291 Patented Feb. 24, 1959 These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a schematic view of the call system employing the pneumatically operated switch of the present invention;

Figure 2 is a vertical sectional view taken substantially upon a plane passing along section line 22 of Figure 1 illustrating the details of construction of the switch;

Figure 3 is a vertical sectional view taken substantially upon a plane passing along section line 33 of Figure 2 illustrating further details of construction of the switch and illustrating the relationship of the contacts to the movable bridging member;

Figure 4 is a detailed sectional view taken substantially upon a plane passing along section line 44 of Figure 1 illustrating the construction of the squeeze bulb;

Figure 5 is a schematic view illustrating a modified form of the switch of the present invention;

Figure 6 is a vertical sectional view taken substantially upon a plane passing along section line 6-6 of Figure 5 illustrating the details of construction of the switch for holding the circuit in closed position until manually released by a nurse;

Figure 7 is a schematic view of another form of the switch of the present invention; and

Figure 8 is a detailed sectional view taken substantially upon a plane passing along section line 88 of Figure 7 illustrating the details of construction of a modified form of switch in which the contact bridging member is retained in circuit breaking relation until such time as manually reset by a nurse attending the patient.

Referring now specifically to Figures 1-4 of the drawings, the numeral 10 generally designates the electric switch of the present invention which includes a generally vertically elongated housing 12 having a semispherical portion 14 at the upper end, with a vertical fiat surface 16, from which a pair of parallel prongs 18 extend for reception in a female plug of any conventional nature and the details of which are not shown. The housing or body 12 is provided with a vertical tubular member 20 forming a vertical passage or path of movement for a steel ball 22. The prongs 18 extend inwardly in the body 12 and project through a portion of the tubular member 20 at diametric opposed points, as illustrated in Figure 3, whereby upward movement of the ball 22 in the tubular member 20 will cause the ball 22 to come into contact with the inner ends of both of the prongs 18, thus electrically connecting the prongs 18, which are also of conductive material as is the ball 22. Thus, the inner end portions of the prongs 18, which are designated by the numeral 24, are actually contacts for completing or breaking a circuit. The upper end of the tubular member 20 is communicated with a passageway 26 for bleeding the upper end of the tubular member 20, thus preventing any possibility of the tubular member 20 becoming air bound. It is pointed out that the steel ball 22 fills substantially the entire cross sectional area of the tubular member 20 so that air entering through the flexible tube 28 and the fitting 30 will cause the ball 22 to move upwardly into contact with the contacts 24. The other end of the flexible tubular member 28 is provided with a generally spherical squeeze bulb 32 having a rigid shield 34 over the major portion thereof whereby some pressure inwardly on the end of the squeeze 22, electric energy is supplied to a solenoid 36 which closes the switch 38 for energizinga signal 40,.such as a light, wherein the switch 38sWill be retained in energized condition until a catch 42 is released by a solenoid 44 that is energized by a manually operated switch 46 .for 'retractingthe catch 42 to permit the switch 381m break away from the solenoid as. The nurseentering the room or answering the call would engage the switch 46 manually and move the same from a position completing the circuit through the signal 46 to a position completing the circuit through the solenoid 44 which would retract the catch 42, thus permitting the switch 38 to return to a normal position.

Reference is now made to Figures and 6 where the numeral 50 generally designates a modified form of the invention somewhat similar in construction to that shown in Figures 2 and '3 but which includes a piston of the cylindrical type designated by numeral 52 movable in a vertical tubular member 29, with the piston 52 being disposed below the contacts 24 with a piston rod 54 extending upwardly between the contacts 24 and outwardly through an enlarged bore 56 receiving a flange 58 on the piston rod 54. A compression coil spring 60 is disposed in the bore 56 between the bottom thereof and the flange S8 for'urging the piston rod 54 upwardly. The outer end of the pistonrod 54 is provided with a thumb engaging knob 52 for resettingthe piston 52 which acts as a movable bridging member between the contacts 24. Also,

the piston rod 54 is provided with a spherical member 64 'exteriorly of the body portion 14 for engagement with a pair of opposed spring fingers 66 which are embedded in the body portion 14 and which retain the piston 52 in a position away from the contacts 24. When the steel ball moves upwardly, the piston 52 will be moved upwardly into contact with contacts 24", thus disengaging the ball '64 from the fingers 66, whereby the spring 60 will hold the piston 52 into engagement with the contacts 24 until the thumb knob 52 is manually depressed for again engaging the ball 64 with the spring fingers 66. Thus, the signal will be energized until manually released.

Inasmuch as the mechanical construction of the switch 50 will maintain the switch in closed position until such time as manually released, the signal light 63 will be retained :in illuminated or energized condition until such time as the thumb knob or button 62 is depressed.

Referring now specifically to Figures 7 and 8 of the drawings, the numeral 7i? indicates another modified form of the switch for energizing the signal light '72 by breaking the circuit between the contacts 24. In this construction, the arrangement of parts is exactly the same as that illustrated at Figure 6 except that the piston rod 54' extends through the piston 52' and the piston 52 is arranged above the contacts 24. piston rod is designated by the numeral 74 and forms an abutment or extension for the steel ball to engage, thus urging the piston rod 54 upwardly, thus disengaging the movable bridging member or piston 52' away from the contacts 2 The pistoni52 will be retained in this position by the spring 6%) engaging thefiange 58, thus maintaining the thumb engaging knob 62 in an elevated position until such time as the same is manually depressed for re-engaging the spherical member 64 with the spring fingers es. in this instance, the signal light or other signal is energized by breaking the circuit between the contacts 24". v

in-the several forms of the invention, the device accom plishes the making or breaking of an electrical circuit from a point remote from any electrical energy by the employment of apneumatic squeeze bulb. This eliminates any possibility of.danger :from electric cords which may become worn or frayed after extended periods of use and whichmay be shorted by contact with liquidsor other wet areas sometimes found adjacent patients and the force necessary to actuate'the switch of the present invention The lower end of they is not materially more than that employed in operating the usual push button type of switch.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and de scribed, and accordingly all suitable modifications and equivalents may be resorted to, falling within thescope of the invention as claimed.

What is claimed as new is as follows:

1. An electric switch comprising a body of insulating material, a pair of spaced parallel prongs extending from said'body for engagement with a socket in an electric circuit, said prongs extending interiorly of the body, a vertically disposed tubular passage in said body with the prongs extending into said passage, a movable contact bridging member disposed in said vertical passage and having substantially an equal cross-sectional :area as the passage, a flexible tubular member connected to the bottom of the vertical passage, and a squeeze bulb connected to said tubular member for supplying pressurized air into the passage under the movabie bridging member for raising the bridging memberinto contact with the inner ends of the prongs, thus completing an electric circuit :through the prongs.

2. The combination of .claim '1 wherein said squeeze bulb is provided witha rigid shield surrounding the major portion thereof, with the shield terminating in an open end whereby pressure may be exerted only on vthe end of the squeeze bulb and the shield will prevent energization of the switch by a' patient .lying or rolling upon the same.

3. The combination of claim 1 wherein said movable bridging member is .in the form of aspherical ball of conductive material.

4. An electric switch comprising a body of insulating material, a pair of spaced parallel prongs extending .from

said body for engagement with a socket in an electric circuit, said prongs extending interiorly of the body, a vertically disposed tubular passage in said body with the prongs extending into said passage, a movable contact bridging member disposed in said vertical passage and having substantially an equal cross-sectional :area as thepassage, a flexible tubular member connected tothe :bottom of the vertical passage, and a squeeze bulb connected. to .said tubular member forsupplying pressurized air into thepassage under the movable bridging member forrraisingthe bridging member into contact with the inner ends or" the prongs, thus completing an electric circuit through the prongs, said bridging member including a ball movable in the passage, a movable bar provided in said pas sage between the ball and contacts for bridging the contacts when said ball engages the bar and moves the same towards the contacts, and resilient clip means interconnectingthe bar and the body for .releasably retaining the bar out of contact with the prongs, and handlemeans connected with the bar for manual resetting of the bar by movement thereof away from the contacts and engagement of the clip means.

v5. .An electric switch comprising a body of'insulating material, a pair of spaced parallel prongs extending .from said body for engagement with a socket in an electric circuit, said prongs extending ,interiorly of the body, a vertically disposed tubular passage in said body withithe prongs extending into'said passage, a movable contact bridging member disposed in said vertical passage and having substantially an equal cross-sectional area .as the passage, a flexible tubular member connected to the bottom oftthe vertical passage, and a squeeze bulb connected to said tubular member for supplying pressurized air into thepassage under the movablebridging .mernber'forraising the bridging member into contact with the inner-ends of the prongs, thus completing an electric circuit'through the prongs, said bridging member including a ball-movable in the passage, a movable bar is provided in-contact with the inner ends of the prongs together with an extension thereon for engagement by the ball for moving the contact bar away from the prongs for actuating a signal by de-energizing the circuit, and manual reset means interconnecting the body and bar for retaining the bar in both of its limits of movement.

6. A manually operable electric switch for use by bedridden patients comprising a body of insulating material having a passageway therein, a pair of contacts embedded in said body in sealed relation with the contacts projecting into said passageway, contact bridging means movably mounted in said passageway for selectively closing and opening a circuit through said contacts, a tube connected with the body insealed relation and communicating with said passageway adjacent one end thereof for urging the bridging means in one direction in the passageway, and a squeeze bulb connected with the free end of the tube in airtight relation thereby completely enclosing the contacts and bridging means and preventing sparks from being emitted when the bridging means makes and breaks the circuit between the contacts, said bridging means including a spherical ball having a cross-sectional area substantially equal to the cross-sectional area of the passageway for movement in the passageway in response to squeezing of the squeeze bulb, a plate-like piston movably disposed in the passageway, said piston being constructed of conductive material and movable in response to movement of the ball between a position in engagement with the contacts and a position spaced from the contacts for closing and opening a circuit between the contacts, 'a rod connected with the piston and extending exteriorly of the body, a thumb knob on the outer end of said rod for manual manipulation thereof, and resilient clip means interconnecting said body and rod for releasably retaining the rod and piston in each of said positions so that the piston will maintain its relationship with the contacts until moved by the ball or until manually moved by manipulation of the knob.

7. In a pneumatically operated switch having a body of insulative material having a passageway with a pair of contacts extending into the passageway, a tube connected with the passageway for supplying air pressure thereto; that improvement comprising a movable piston disposed in said passageway and having a cross-sectional area substantially equal to the cross-sectional area of the passageway, said piston being constructed of conductive material for completing a circuit when engaged with the contacts and interrupting a circuit when disengaged from the contacts, said piston being longitudinally movable in the passageway in response to variations in air pressure in the tube and passageway, an elongated rod rigidly connected with the piston and extending axially thereof, said body having a bore slidably receiving said rod with the outer end of the rod extending exteriorly of the body, a thumb knob on said rod for manually setting the piston in an initial relation with the contacts, slip means interconnecting the rod and body releasably retaining the piston in the initial relationship, said clip means also serving to retain the piston in a second relationship with the contacts after movement away from the initial relation in response to change in air pressure in the tube and passageway until the thumb knob is manually moved for moving the piston back to the initial relation with the contacts.

References Cited in the file of this patent UNITED STATES PATENTS 831,599 Browne Sept. 25, 1906 1,3 54,999 Pieri Oct. 5, 1920 2,558,235 Castellano June 26, 1951 2,631,203 Mekelburg Mar. 10, 1953 FOREIGN PATENTS 854,131 France Jan. 4, 1940 963,901 France Ian. 18, 1950 

